1. Field of the Invention
The invention relates to a zoom lens, and in particular relates to a zoom lens capable of preventing a lens group from lateral movements in a collapsing operation.
2. Description of the Related Art
In recent years, portable electronic products and lenses applied therewith have been miniaturized and lightened to satisfy users' requirements on portability and operational conveniences.
A conventional zoom lens generally includes a plurality of lens groups which are capable of performing various operations such as zooming and focusing. When the zoom lens is retracted (in a collapsing operation), one of the lens groups (e.g., the third lens group) is moved along an optical axis, contacted by a stop to rotated, and leaves a space for other lens groups to enter, thereby attaining the purpose of miniaturizing the zoom lens.
In operation, however, the third lens group in rotation is susceptible to lateral movements due to a clearance between the internal and external frames which are utilized to support the third lens group. As a result, the optical axis deviates from the preset position and the whole optical performance of the zoom lens is significantly influenced.